Apparatus for freezing bulk materials



Nov. 17, 1942. c. A. BAKER APPARATUS FOR FREEZNG BULK MATERIALS c l oATTORNEY Nav. 17, 1942. C. A. BAKER v v 2,302,169

APPARATUS FOR FREEZING BULK MATERIALS Filed June 2a. 1940 s sheets-sheet2' INVENTOR NOV. 17, 1942. C, A BAKER 2,302,169

APPARATUS FOR FREEZING BULK MATERIALS Filed vJuri@ 28, 1940 :ssheets-sheet 3 a y INVENTOR Patented Nov. 17, 1942` APPARATUS FORFREEZING BULK MATERIALS Chester A. Baker. Glen Ridge, N. J. ApplicationJune 28, 1940, Serial No.` 342,966

17 Claims.

This invention relates to quick freezers, and

- more particularly to an apparatus of this character for rapidlyfreezing food products, `such as peas, beans, cherries, crushed fruits,small sh, oysters, and other perishable products of liquid, solid, orsemi-solid character, in bulk.

It is Well known that products of this' character must be frozen rapidlyto avoid objectionable change in their cell structure and other physicalproperties, but dii'iculties have heretofore been encounteredincollective freezing of large quantities of foodstuffs in bulk because ofinsufficient contact of the particles with -heat interchange surfacesdue to limitations in time of travel of the product through the freezerand size f the equipment because many food products are rapidlyperishable and should be processed at the source of production beforebacterial action begins, consequently expensive and heavy equipmentheretofore employed is not suitable for the purpose.

It is, therefore, the principal object of the present invention toprovide apparatus of high capacity but relatively low initial cost,capable of economically freezing food products While in continuousmovement.

Other objects of thev invention are to provide an apparatus readilyadapted for transportation from one source of food products to another;to

provide for initial turbulence of the particles to be frozen so as topreventfreezing thereof to the heat exchange surfaces with which theparticles are contacted, to provide for movement of the products throughthe apparatus with less turbulence and more compact order, and finallyto provide means for promoting separation of the the invention, Iv haveprovided improved structure, the preferred forms of which-areillustrated Y in the accompanying drawings, wherein:

frozen particles before discharge thereof from the apparatus.

It is also an object of the invention to apply a frozen mist or frost tothe frozen materials prior to nal packaging thereof, so-as 'to maintainthe frozen materials in a fully hydrated condition over long periods oftime.

A further object of the invention is to provide for precoolng a productby contact with cooled air prior to introduction thereof into thefreezing chamber in a manner to reduce the surface mois# surfaces of theconveyor, while promoting frosting of the individual particles which arefrozen in the equipment.

A further object is to provide an apparatus thatmay be readily cleanedand kept in sanitary condition.

ture and prevent frosting of the heat transfer Fig. 1 is a longitudinalsection through a quick freezer constructed in accordance with thepresent invention.

Fig. 2 is a longitudinal section of the conveyor shaft support at oneend, of the freezer, partly illustrating the refrigerant inlet andoutlet cnnections therewith.

Fig. -3 is an enlarged section through a portion Iof the freezer wall,partly illustrating the nozzle for discharge of -a frosting medium ontothe particles of the frozen product prior to their discharge from thefreezing chamber.

Fig. 4 is a cross-section through' the freezer on the line 4 4 of Fig.1.

Fig. 5 is a similar Fig. 1.

Fig. 6 is a cross-section on the line 6 6 of Fie. 1.

Fig. 7 is a side elevational view 'showing the freezing chamber removedfrom the conveyor for cleansing purposes, parts being broken away toshorten the illustration.

Fig. 8 is a longitudinal section through a modified form of theinvention.

Referring more in detail to the drawings:

I designates a quick freezer constructed in accordance With the presentinvention for contin-A uous processing of large quantities of perishablesection on the line 5-5 of commodities in the bulk. The freezer includesa' chamber 2, preferably iin the form of a cylinder having an innerannular Wall `3 encircled by a spaced outer wall, 4 to provide arefrigerant containing or expansion space 5 therebetween whereby theinner wall forms a heat exchange surface `6. In the illustratedinstance, one end of the inner Wall is provided with an annular-flange1, inset within the 'outer wall 4 and secured thereto in any suitablemanner to provide a fluid-tight joint. The opposite end of the innerwall has a similar but larger flange 8 lapping a corresponding flange 9on the outer wall 4 to close that end of the expansion space 5. Alsofixed to the respective ends of the outer wall are rings III and I I toattach heads I2 and lI3 which close the ends of the freezing chamber,the head I3 being secured to the ring Il by fastening devices such asbolts I4.

A refrigerating medium, for example a readily volatile liquid, isadmitted to the space 5 through In accomplishing these and other objectsof connections I5 and I 6 of a manifold I1. that is supplied through aconduit I8 leading to a-suitable refrigerant compressing and condensingapaccordance with paratus (not shown). acting in the space 5 freezingchamber through the wall 3 thereof in well known refrigeration methodsand is discharged through connections i9 and 28 into a manifold 2| forreturn to the compressor apparatus through a pipe 22.

The freezing chamber thus described is preferably arranged with the axisthereof in horizontal position whereby a product to be frozen is movedlongitudinally thereof from an inlet 23 in the head by means of aconveyor 25. Connected with the inlet 23 is a duct 26 leading Therefrigerating medium from a hopper 21 through which' the product isdischarged in a substantially continuous stream to the freezing chamber.The outlet opening 24 is connected with a discharge spout 28 so that thefrozen product may be discharged therethrough into suitable containers(not shown).

In accordance with the present invention the conveyor 25 is constructedto constitute a refrigerating element for furnishing additional heatexchange surface within the freezing chamber, thereby assuring rapidfreezing vin a relatively short period of time with a. more compactequipment. bular shaft 29 having the ends thereof projecting throughbearing openings 30 and 3| in the respective heads I2 and I3 whichmountsuitable bearings 32 and 33, the bearing 33 being retained in aclosed housing 34 nxed to the head I3 and the bearing 32 being retainedin a plate 35 cooperating with a recess 36 in the head I2. about theshaft with suitable packings as and 38 respectively, the packing 31-being retainedin a plate 39 attached to the inner face of the head I2and the packing 38 within the opening 3I and a registering recess 48provided in the housing 34 as clearly shown in Fig. 1. The end of theshaftvwhich is lournaled in th'e bearing 33 is closed by a plug 4I insetwithin the end thereof and in substantial registry with the head I3. Theopposite end of the shaft projects through the bearing 32 into asectional packing box 42 and is=shown as threadedly connected with ahead 43 on a solid shaft extension 44. -The shaft extension 44 isjournalled within an antifriction bearing 45 carried within a bushing 46that is supported by a collar 41 in turn being carried by arms 48 whichare fixed to a ring 49 that abuts against the head I2. The ring 49 isthus located in registry with the nanges 8 and 9, so that it may besecured with the same fastening devices such' as bolts 58. The innerrace of the bearing 45 abuts against the shoulder formed by the head 43and the outer race thereof is retained in position by a cap 5I which issecured to the bushing 46.by fastening devices as indicated at 52. Theshaft extension 44 extends through the cap 5I and is connected by means0f a coupling 53 with any suitable driving mechanism (not shown) whichis capable of rotating the conveyor at the desired speed.

- Fixed on the conveyor shaft is a helical wound metal ribbon 54, ofsuitable width so that the outer edge thereof substantially contacts theheat exchange surface 6 of the chamber 2. The nights 55 of the helix arespaced apart to cooperate with the shaft 29 and the Wall 4 in forming ahelical passageway 56 extending substantially the length of the freezingchamber and through winch a product to be frozen is proextracts heatfrom the I2 to an outlet 24 in the head I3 v The conveyor thereforeincludes a tul 41, the collar I gressively advanced incidental torotation of the conveyor. In order that the nights of the conveyor mayhave positive heat exchange surfaces so that th'e ventire surface of thepassageway 56 is effective, each night hasnxed thereto the convolution51 of a helical wound duct in which a refrigerating medium iscirculated. The front end 58 of the duct is connected with thepassageway 59 of the shaft through a. lateral opening 69 while the otherend 6I extends through an opening 62 at that to connect with an axialsupply duct 63 having connection with the head 43, previously described.The terminal 6I is suitably sealed in the shaft as by welding to providea leak-tight joint. Y The packing box 42 includes a pair of ringlikesections 64 and 65 of larger diameter than the shaft to form annularpassageways 66 and 61. The outer ends of the sections are closed byheads 68 and 69 having nange portions 19 and 1I respectively encirclingthe shaft head 43 and the projecting endof the tubular shaft 29. Thesections are respectively secured t0 the bushing 46 and plate 35 bysuitable fastening devices 12 and 13. The flanges 19 and 1I providerecesses 14 and 15 to receive packing rings 16 and 11 to seal the outersides of the passageways 66 and 61 and prevent leakage therethrough.

y The sections 64 andl 65 abut against opposite sides of a partition 18that is retained in concentric relation therewith by fastening. devices19 y extending through nanges 88 on the ring-like sections and throughthe partition plate 18 as shown in Fig. 2. 'I'he plate 18 also includesa nange 8l which encircles the shaft to provide space for receivingpacking rings 82 similar to the packing rings 16 and 11 at the oppositeends of the sections. The packing rings are yieldingly pressed intosealing contact with the shaft by springs 83 and 84 as shown in Fig. 2.The passageway 66 connects with the conduit 63 through radial ports 85connecting with an axial port 86 and th'e passageway 61 connects withthe passageway 59 of they shaft through openings 81. Refrigeratingmedium is supplied to the passageway 66 through a duct 89 whichmayconnect with the duct I8, and expended refrigerant is discharged fromthe passageway 61 through a duct 88 that may connect with the returnpipe 22, previously described.

.f I have found it desirable to effect turbulence of the particles whennrst admitted to the freezing chamber so that they do not linger incontact with any one portion of the heat exchange surface until thesurface moisture thereon has evaporated or frozen, otherwise there maybe a tendency for the particles to freeze together or to the surface ofthe conveyor. In order to promote this turbulence, at least the nrstnights at the inlet end of the conveyor are spaced apart a.

than the intermediate flights to give greater room for the particles andfreedom of movement therefor. The turbulence thereof may be increased byproviding the nights of the conveyor with suitable projections 98 o rother means for picking up and carrying Y the partcles as the conveyoris rotated. Withthls arrangement the particles are carried byr theprojections up the side wall of the chamber to a point where they rolloff the projections and drop back over the top of the shaft to be caughtagain by the projections. The particles `are thus retained in loosecondition for a greater period of time before they become more greaterdistance end of the shaftcompacted bespout 28.'

Itis well known that frozen materials carried in freezer storage overlong periods of time have a tendency to dehydrate or lose a substantialamount bf their moisture content. I therefore have provided means forapplying a frozen Water mist or frost to the frozen materials beforefinal packaging so that they may be maintained in a fully hydratedvcondition for a considerable time after packaging. This is effected bymeans of a high. pressure insulated spray nozzle 9| which is mounted inthe wall of the freezer chamber and arranged to direct a spray of liquidbetween selected flights of the conveyor, preferably near the dischargeend. At this point the cold is so intense that the fine particles ofmist or water vapor are instantly frozen into snow, which combines withthe frozen m'aterial to impart a sparkling appearance to the product aswell as providing va moisture reserve during the time that the packagedproduct is in storage.

In using an apparatus constructed and assembled as described in Figs. 1to 7 inclusive, liquid refrigerant is delivered through the pipes 89 andI8 for evaporation in the space 5 to effect extraction of heat from theinterior of the chamber, and for expansion in the coil of the conveyor,to likewise extract heat therefrom.` The refrigerant flows to the coilby way of the ports 85 and 86, and duct 63, to the entrance 6| of thecoil. The evaporated refrigerant flows from the coil at 60, throughpassageway 59 of the shaft,

openings 81, and passageway 61, for return through the duct 88. Thevarious packings maintain seals to prevent leakage of the refrigerantinto the freezingchamber, vthe shaft bearing 45, or short circuitingthrough the partition plate 18.

The product, for example peas, is fed into the hopper 21 and dischargedtherefrom through the duct 2 6 and inlet 23 into the freezing chamber tobe caught by the first nights of the conveyor for agitation by theprojections 90. The projections 9|) pick up the particles and carry themup the side of the heat exchange surface 6 to a point where they fallback upon the' shaft and gravitate down the sides of the conveyoriiights. The peas are therefore .in constant movement relatively to theheat absorbing surfaces, while the surface moisture is frozen orevaporated so that the peas will not freeze on the heat exchangesurfaces. The peas will, however, be

advanced between the iiights of the conveyor and individually contactedwith the heat exchange surfaces suiiiciently to effect rapid freezingthereof. By the time the peas have reached the spray nozzle, they arecompletely frozen and with such rapidity that the cellular structure hasnot been destroyed. When they' pass under the spray 9, the mistdischarged therefrom freezes in the form of frost to enhance theappearance thereof. When the peas finally reach the wider spaced flightsat the discharge end of the conveyor, they loosen from contact with eachother and are discharged through the spout 28.

When it is necessary to clean the equipment between runs, the freezingchamber is readily unbolted from the head I2 and slid retractively awayfrom the conveyor, asvnshown in Fig, '1. All the parts arev thus`readily exposed for sterilization by steam.. If' desired',` therefrigerant .connection forx thel chamber may be iiexible so that thechamber mayfbermnvedwithout disconnecting the supply and return pipes.While the apparatus may be supported in any suitable manner, the head I2preferably includes a fixed staticiV 92, and the chamber may besupported from a track or a suitable tackle (not shown).

In the form of the invention shown in Fig. 8,

I have provided for positive circulation of cold A air in pre-coolingcontact with the product prior to its admission'into the freezingchamber. This is effected by providing the outer wall of the cylinderwith an insulated jacket 93 which is spaced therefrom to provide an airpassageway 94 therebetween. Air is drawn from the space 94 through aduct 95 connected with the suction side of a blower 96. VThe dischargeside of the blower is connected by a duct 91 with the product supplypipe 98. As in the preferred form, the pipe conducts the product from ahopper 9.9

yto tHe inlet openingl of the freezer. The pipe 98 is provided with airoutletI openings I 0| connected with a suction manifold |02 whichconnects through a port |03 with the space 94 so that the air isreturned for recooling. It is thus obvious that chilled air is contacteddirectly with the product prior to its admission to the freezing chambersopas to' extract surface moisture therefrom. This contact of the airalso promotes feed of the product and effects turbulence thereof. It isobvious that air in the jacket serves as an insulator and conserves therefrigerant because the external heat, normally absorbed by therefrigerant, is taken from the air which is used in precooling theproduct. y

The operation of the form .of the invention shown in Fig, 8 is otherwisethe same as that of the preferred form.

From the foregoing it is obvious that I have provided a freezer havingan extremely rapid heat exchange so that particles are quickly frozen.The greatly increased refrigerating surface afforded by the conveyorpermits of a relatively short cylinder so as to occupy a minimum ofspace, thereby particularly adapting the apparatus for portability sothat it may be conveniently carried to the source of the product wherethe product may be processed when in the most satisfactory condition andbefore bacterial action begins.

What I claim and desire to secure by Letters 1 Patent is:

1.An apparatus of the character described, inv cluding a freezingchamber having an inlet and an outlet for a product to be frozen, meansfor moving the product through the freezing chamber, and means carriedby said moving means and forming a closed passageway for 'thecirculation of a refrigerating medium in indirect heat exchange relationwith the product moved through the freezing chamber.

2. An apparatus of the character-described, including a freezing chamberhaving` an inlet and an outlet for a productl tubeA frozen, means formoving the producty through the freezing chamber, means in directcontacty with said moving means for circulating a refrigerating mediumin v indirect heat exchange relation with the product moved through thefreezing chamber, and means on themoving means for agitating theproduct.

3. An apparatus of the character described, including a freezing chamberhaving an inlet and 10. an apparatus of :sacarse 4 an outlet for aproducttobe irozema screw type ciuding a freezing chamber having aninlet and conveyor rotatably supported in the chamber to an outlet, anda screw type conveyor rotatable move Vthe product from the inlet towardthe outwithin the chamber and having nights o1 variable let. the nightsof said conveyor having refrige'rvspacing to enect movement of a productintro" ant passages for a refrigerant, and means sup- 5 duced throughthe inlet at variable speeds plyingarefrigeranttothepassag. throughselected portions o! the chamber, the` 4. An apparatus ofthe characterdescribed innights adjacent the inlet and outlet having the cludlng afreezing chamber having an inlet and widest spacing. ancutletforaproducttobefrozemahollw ILAreingchamberhavinganinletandan shaftiom'nalled in the freezing chamber, c 10 outlet, a duct for feedingmaterial through the veyor nights on the shaft,I a coil coextensive withinlet to be `frozen while moving toward said outsaid nights and havingone end connected with let, and means associated with said duct forp'r'e-` the shaft, a supply duct coextensve with thecoolingthematerlalhefore discharge through the shaft and connected withthe other end of the inlet oftheireezlng chamber. com and return andsupply pipes respectively l5 12. freezing chamber having an inletand anconnected with the shaftu and .supply duct outlet, a duct for feedingmaterial through the whereby a rerigerating medium is circulated inletto be frozen while moving toward said outthmughsaidcgn, let, a jacketencircling the chamber to form an 5. An apparatus of the characterdescribedinair cooler, and means :for circulating air from cluding afreezing chamber having an inlet and 20 said cooler into the duct forprecooling the matean outlet for a product to be frozen. a hollow rialand for returningtheairtothe cooler. shaft iournalled in the freezingchamber, con- 13. Anapparatus ofthecharacter described inveyor nights onthe shaft, a coil coextensive with cluding, a freezing chamber, meansfor conveying said nights and having one end connected with a materialto be :frozen through the freezing the Shaft, a supply duct coextensivewith the '25 chamber, said conveying means beingarranged shat andconnected with" the other end of the to agitate said material in thefreezing chamber,` coil, packing boxes encircling the shaft and havandmeans for discharging a mist into the freeiing passages connected withsaid supply duct and ing chamber and onto the material. shaft, andrefrigerant circulating ducts con- 14. .anapparatusoithecharacterdescribedinnested with the passages of the packing boxes. 3o cloning, afreezing chamber, a conveyor rotatable 6. an apparatus for freezingfoodstuffs includwithin the chamber and having nights to effect ing :afreezing chamber, means in the chamber movement of a material to befrozen, and means for agitating the foodstuls therein, means for fordischarging a mistbetweenselected nights o! supplying a rerigerantinheat exchange relation the conveyor to provide the material with arewith said foodstuls while under agitation.' and 35 serve moisturesupply. means movably supporting the agitating means 15. Anapparatusofthe character described inand said refrigerant supply means formovement cluding, a freezing Vchamber having an inlet and in saidfreezing chamber. an outlet forl material frozen in said chamber, L .anapparatus for freezing foodstuiis includmeans for conveying the materialthrough the ing a freezing chamber. means in the chamber 4D freezingchamber, means for supplying a refrigfor agitating the foodstuistherein, means for erant to the freezing chamber, and means for.supplying a retrigerant in heat exchange relation discharging a mistinto the :freezing'chambersepwith said foodstuis while Vunder agitation,and arate from said refrigerant at a point near said means movablysupporting said atating means outlet to provide a reserve moisturesupply for and said refrigerant supply means in said freez- 45thematerial. ing chamber. said supporting means forming a 16. 4Anapparatus of the `character described inconveyor for `advancing theoods'tuis through cluding, a freezing chamber, a conveyor rotatable thechamber. within the chamber and having nights of variable 8. Anapparatus of the Vcharacter described .inspacing .to elect movement of amaterial to be cluding a freezing chamber having :an 'inlet and 50frozen at variable speed, and means for dischargan outlet, Iand 'a:screw type conveyor rotatable 'ing a mist onto the material selectedwithin the ychamber and having nights of variable nights of narrowerspacing to provide the matespacing to :elect movement of a productintrorial'with areserve moisture supply. duced through the inlet `atvariable .speeds 17. .An apparatus yof the character describedlnvthrough selectedportionsof the-chamber. '55 cluding a vfreezing:chamber having an inlet and 9. nn apparatus of the Icharacter`described .inan outlet for material to be frozen, a conveyor cluding afreemg chamber having 1an inlet and having nights of variable spacing tomove the fan outlet, and a screw type `conveyor rotatable material atvariable speeds, :said nights adjacent within "the chamber land havingnights of var' the inlet and outlet having 'wider spacing, and iablespacing lto eiiect movement of a product in- '50 means for discharging aonto the material troduced through vthe inlet at variable .speedsbetween the endmost nights of narrow spacing through selected of thechamber, the nearest said outlet to provide the material with a nightsadjacent the inlet having the yWidest reserve moisture supply; spacing.

the character described ing5 A. BAKER.

